Film-forming composition comprising a silica-urea formaldehyde polymer flatting agent

ABSTRACT

THIS DISCLOSURE RELATES TO THE USE OF A COMBINATION OF NON-POROUS MATERIALS COMPRISING A CERTAIN GROUP OF UREAFORMALDEHYDE POLYMERS AND A CERTAIN GROUP OF PYROGENICALLY PREPARED COLLOIDAL SILICAS AS FLATTING ADDITIVES IN THE PREPARATION OF FLATTED COMPOSITIONS SUCH AS PAINTS, LACQUERS, VARNISHES AND THE LIKE.

United States Patent F 3,793,302 FILM-FORMING COMPOSITION COMPRISING ASILICA-UREA FORMALDEHYDE POLYMER FLATTING AGENT Gregor Berstein, Newton,John F. Hardy, Andover, and Leonard H. Doppler, Lexington, Mass.,assignors to Cabot Corporation, Boston, Mass.

No Drawing. Original application Oct. 12, 1971, Ser. No. 188,563, nowPatent No. 3,714,085. Divided and this application Nov. 24, 1972, Ser.No. 309,173

Int. Cl. C08h 21/12; C08g 51/04; C08h 17/02 U.S. Cl. 260-15 14 ClaimsABSTRACT OF THE DISCLOSURE This disclosure relates to the use of acombination of non-porous materials comprising a certain group ofureaformaldehyde polymers and a certain group of pyrogenically preparedcolloidal silicas as flatting additives in the preparation of flattedcompositions such as paints, lacquers, varnishes and the like.

This is a division of application Ser. No. 188,563, filed Oct. 12, 1971and now Pat. No. 3,714,085.

This invention relates to new and improved flatted and semi-glosscompositions having desirable physical properties such as stability ofgloss and good dispersion. More particularly, this invention isconcerned with novel flatted and semi-gloss compositions comprising afilm-forming organic material, an organic solvent and as a flattingadditive an effective amount of a combination comprising certainurea-formaldehyde polymers and certain colloidal silicas as hereinafterdescribed.

It is well known that many systems require a matte or semi-matte finish,such as in the field of wood products including prefinished paneling,flooring, furniture and the like. In order to impart such finishes, itis necessary to employ flatting agents capable of imparting suchcharacteristics. Accordingly, flatting agents are conventionally used invarnishes, lacquers and the like to prepare compositions which whenapplied to a base substrate such as wood yield a delustered finish orproduce a finished surface having reduced gloss. The conventionally usedflatting agents comprise finely divided particles capable of diffusinglight reflections and thereby reducing the gloss of the compositions.Among the varied materials which have heretofore been employed asflatting agents there are included natural materials such as gums,resins and siliceous materials, and synthetic materials such as metallicsoaps and finely divided siliceous materials.

The most widely used flatting agents have been silica gels of the typecommonly referred to as silica aerogels wherein the original gelstructure is maintained, and silica gels of the type known as silicaxerogels wherein the original gel structure is destroyed. While thesilica gels are used extensively in various applications, there are,however, several disadvantages related thereto. For example, a majordisadvantage of silica gel flatting agents is the tendency on standingto cause a settling out from the flatted composition of a solidprecipitate containing the silica. Before the flatted composition may beused, it is I therefore essential that the solid layer of settled outmaterial be redispersed throughout the composition. It has been foundextremely difiicult to redisperse this precipitate and, in someinstances, attempts to redisperse the precipitate have failedcompletely. A further disadvantage of the prior art conventionallyemployed flatting agents involves the porosity of such agents whichnecessitates grinding prior to usage. The grinding action has been foundto affect adversely the reproducibility of the desired flatting effect.

3,793,302 Patented Feb. 19, 1974 It is, accordingly, a principal objectof the present invention to provide a novel combination of non-porousmaterials which require no grinding to impart desired flatting effects.

It is also an object of this invention to provide a novel combination ofcertain non-porous urea-formaldehyde polymers and certain non-porouscolloidal silicas which is useful, without grinding, as a flattingadditive for preparing delustered clear finishes.

It is a further object of this invention to provide a novel combinationof certain non-porous materials which impart desired flattingcharacteristics merely by varying the ratio of the components of thecombination.

It is also an object of this invention to provide novel and improvedflatted or delustered finish compositions wherein the flatting additivecomprises a combination of certain non-porous urea-formaldehyde polymersand certain non-porous colloidal silicas.

It is a further object of this invention to provide novel and improveddelustered clear finish compositions, particularly varnishes andlacquers, wherein reproducible gloss effects are achieved as a result ofhaving only to stir in the flatting agents and thereby eliminate thenecessity for pebble milling or grinding.

Other and different objects, advantages and features of the presentinvention will become apparent to those skilled in the art uponconsideration of the following detailed description and claims.

In accordance with the invention, it has been found that the above andstill further objects are achieved by the utilization of a certain groupof non-porous urea-formaldehyde polymers in combination with a certaingroup of non-porous colloidal silicas as a formulated flatting additivein the preparation of the present delustered coating compositions,including paints, lacquers and varnishes. As noted previously, the novelcombinations of the present invention comprising two specific non-porousmaterials necessitate only a stirring-in or dispersing action ratherthan a grinding or milling action and, therefore, impart to resultantcompositions containing such blends a high degree of reliability forobtaining reproducible gloss readings.

Generally speaking, the amount of the novel combination flattingadditive employed in the preparation of the flatted and semi-mattecompositions of the present invention may vary over a wide range withthe sole requirement that the amount used be sufficient to decrease ordeluster the gloss of the composition without adversely affecting theclarity of the composition. It is obvious, therefore.- that the amountof flatting additive to be employed depends upon several factorsincluding the particular filmforming organic solid employed, the amountof organic solvent used, and the extent of flatting desired. Normally,however, amounts ranging from about 5 to about 30 percent by weight ofthe combined flatting additive, based upon the weight of thefilm-forming organic material, are utilized in the preparation of theflatted compositions. Furthermore, the additive combination is comprisedof an amount varying from about 20 to about percent by weight based onweight of the total combination of the non-porous urea-formaldehydepollmer and an amount of from about 80 to about 20 percent by weightbased on the weight of the total combination of the non-porous colloidalsilica. In a preferred embodiment, however, the additive combinationcomprises an amount of from about 40 to about 60 percent by weight ofthe non-porous ureaformaldehyde based on the weight of the totalcombination and an amount of from about 60 to about 40 percent by weightof the non-porous colloidal silica based on the weight of the totalcombination.

The film-forming organic polymeric materials suitable for use inpreparing the present composition, particularly varnishes and lacquers,include the following. Oil varnishes which are unpigmented oil-basepaints comprise a solvent such as turpentine or petroleum naphtha and abinder that forms a film by oxidation or polymerization such as dryingoils alone or in combination with natural or synthetic resins,chlorinated rubber and the like. Spirit varnishes which are suitable foruse with the present invention are composed of a solvent such asmethanol, methyl isobutyl ketone, butyl acetate, toluene, or the likeand a binder that forms a film by evaporation of the solvent such as theshellac, cellulose ester or ether, alkyd and phenolic resin varnishes.Specific examples of drying oil varnishes include unsaturated fatty oilresin varnishes such as linseed oil and tung oil varnishes; naturalresin unsaturated fatty oil varnishes such as rosin-linseed oil orrosin-tung oil varnishes; synthetic resin unsaturated fatty oil or alkydvarnishes such as maleic ester gum, modified phenolic or modifiedresin-pentaerythritol resin in combination with unsaturated fatty oilssuch as linseed oil or tung oil. The alkyd resins contemplated, asdescribed in The Condensed Chemical Dictionary (6th ed., 1961), aregenerally prepared by the union of dibasic acids or anhydrides,especially phthalic anhydride, with a polybasic alcohol such asglycerine. Modification of the alkyd resins may be accomplished by usingother anhydrides such as maleic anhydride, dibasic acids, glycols,'polyols or other substances the most common and notable of which arevarious natural oils or the acids derived therefrom. The use of linseedoil or linoleic acid or similar drying oil materials results in anoxidizing alkyd, while the use of essentially saturated oils and theirderivatives produces non-oxidizing alkyd resins.

Also suitable for use with the process of the present invention arelacquer compositions which are solvent-base paints that form a film byevaporation of the solvent employed such as acetone, ethyl alcohol,methyl isobutyl ketone, ethyl acetate, butyl acetate, benzene, tolueneor xylene. Among the binders or film-forming constituents of the lacquercompositions are cellulose esters or ethers such as celluloseacetate-acetone lacquer; maleic rosin lacquer; nitrocellulose lacquersoften in combination with alkyd resins; polyvinyl chloride lacquers,vinyl chloridevinyl acetate copolymer lacquers; and acrylic lacquers.The acrylic lacquers which are particularly suitable for use herein maybe defined as essentially non-aqueous or solvent type systems in whichthe major portion of the resin is a thermoplastic or thermosettin-gacrylic resin produced by the polymerization of monomers such as acrylicacid, methacrylic acid, and their derivatives, with or without minoramounts of other compatible monomers. Examples of typical resins of thistype are acrylic acid, methacrylic acid, methyl acrylate, ethylacrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethylmethacrylate,

. n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate,n-octyl methacrylate, n-lauryl methacrylate, ntetradecyl methacrylate,n-hexadecyl methacrylate and the like. These monomers are merely typicalof those known to the art and described in Organic Coating Technology byPayne (Wiley and Sons, New York, 1954). For example, many other homologsof these monomers can be used in the present invention as well ascopolymers of such monomers. Other ingredients which can be included inthe acrylic type resin are additional resins such as melamine, styrene,epoxy or other such compatible resins or mixtures thereof. In suchmodified acrylic resins systems, the proportion of acrylic monomer tomelamine, epoxy or other resin may vary depending upon the propertiesdesired in the finished product but the acrylic resin componentgenerally comprises the major constituent of the resin product.

Also particularly well suited for use in the present invention arepolyurethane resins of both the thermoplastic or thermosetting types.The polyurethane resins are formed by reacting an isocyanate such astoluene diisocyanate or diphenylmethane-4,4'-diisocyanate with abydroxyl group-containing material such as polyethers, especiallypolyoxypropylene, polyesters, castor oil, monoglycerides, diglyceridesor glycols.

The urea-formaldehyde component of the combined flatting additive is apolymer characterized as being nonporous, infusible, insoluble,particulate and having a molar ratio of urea to formaldehyde rangingfrom about 1:1 to about 1:2 and a specific surface area ranging fromabout 5 to about 100 m. g. In a preferred embodiment, however, thenon-porous, insoluble, infusible particulate urea-formaldehyde has amolar ratio ranging from about 1:1 to about 1:2 and a specific surfacearea ranging from about 50 to about m. /g. The ureaformaldehydepolymeric products of the present invention are readily prepared by anyof several methods known to the art. For example, the non-porous,insoluble, infusible products may be obtained by utilizing a singlestage process or a two stage process, in both of which instances thepolymers are prepared so as to contain the desired molar ratios of ureato formaldehyde. In more detail, the two stage process entails initiallyreacting urea with formaldehyde in an aqueous solution to form a solubleand fusible precondensate, and thus to produce in the presence of asuitable curing catalyst and at elevated temperatures an insoluble andinfusible product which may form a gel or a precipitate. Alternatively,when utilizing the single stage process, all of the reactants andprocess additives are added at the outset and the reaction proceedsdirectly until a cross-linked, insoluble and infusible polymer gel isformed. In each instance the resultant polymer gel is neutralized andrecovered by filtration or centrifugation and is dried by anyconventional technique such as spray drying, air drying, azeotropicdistillation or other means for effectuating contact and convectiondrying. Depending on the reaction conditions employed, the insoluble andinfusible reaction products may be produced directly in comminuted formas a powder or a granulate. In the event that the reaction product isnot obtained in such a form, the product may be comminuted ordeagglomerated to a finely divided form utilizing any suitable meanssuch as a ball mill, a pounding mill, a roller mill, an impact mill oran air jet mill.

The acid curing cataysts suitable for use in preparing the insoluble,infusible, non-porous urea-formaldehyde polymers of the presentinvention include any of the conventional acid catalysts such assulfuric acid, phosphoric acid, hydrochloric acid, nitric acid; organicacids of medium strength having a pK value less than 4 such as formic,oxalic, maleic, succinic and chloroacetic acids; and the like. It ispreferred, however, to employ as the acid curing catalyst sulfamic acidor a water-soluble ammonium hydrogen sulfate having the general formula,RNH SO H, wherein R is a radical selected from the group consisting ofhydrogen, alkyl, cycloalkyl, hydroxyalkyl, aralkyl or aryl. Exemplarywater-soluble ammonium hydrogen sulfates are ammonium hydrogen sulfate,methylammonium sulfate, phenylammonium hydrogen sulfate, benzylammoniumhydrogen sulfate and the like.

In an optional preferred embodiment of the present invention,water-soluble macromolecular organic substances which greatly increasethe viscosity of aqueous solutions, referred to hereinafter asprotective colloids, may be present in the reaction mass during theprecipitation of the urea-formaldehyde condensation products. Typicalexamples of such protective colloids are natural substances such asstarch, gelatin, glue, tragacanth and gum arabic; modified naturalsubstances such as carboxymethylcellulose, the alkali metal salts ofcarboxymethylcellulose, particularly the sodium salt ofcarboxymethylcellulose, methylcellulose, ethylcelluose,betahydroxyethylcellulose, alkali metal alginates and the like,synthetic polymers such as polyvinyl alcohol, polyvinyl pyrrolidone,water-soluble polymers and copoymers of acrylic or methacrylic acids andalkali metal salts thereof, salts of maleic acid-containing copolymers,styrenemaleic anhydride copolymers, polyhydrochlorides of homopolymersand copolymers of vinylpyridine and the like. The amounts of protectivecolloids to be employed are dependent on the type, chemical structureand molecular weight thereof. However, the protective colloids aregenerally used in amounts ranging from about 0.1 to about percent byweight based on the weight of the urea and formaldehyde reactants.Preferably, amounts of the protective colloid ranging from about 0.5 toabout 5 percent by weight based on the weight of the urea andformaldehyde reactants are used. In practice, the protective colloid maybe added, in the case of the single stage process for preparing thepolymers, to the precondensate of urea and formaldehyde at any stage ofthe wet end of the manufacturing process. Alternatively, with similarlyadvantages results, the protective colloid may be added after theformation of the urea-formaldehyde precondensate in a two stage processfor preparing the insoluble, infusible urea-formaldehyde polymers.

In a further preferred embodiment of the present invention, theurea-formaldehyde polymers useful in pre-. paring flatting additives areprepared by a process which entails the use of sulfamic acid or awater-soluble ammonium hydrogen sulfate as hereinbefore defined as acuring catalyst in combination with a protective colloid in theconversion of a precondensate of urea and formaldehyde into acrosslinked gel. In more detail, a precondensate of urea andformaldehyde having a molar ratio of from about 1:1 to about 1:2 of ureato formaldehyde is formed at a temperature varying from about 40 toabout 100 C. and at a pH range of from about 6 to about 9 and for aperiod of time sufiicient to permit the greater portion of theformaldehyde to be reacted with the urea. A protective colloid, such asthe sodium salt of carboxymethylcellulose, is added to the precondensateat any time during the production thereof, or is added separately as asolution to an initially prepared precondensate. To the resultantprecondensate there is then added, with agitation, a solution ofsulfamic acid or a water-soluble ammonium hydrogen sulfate at a temperature ranging from room temperature to about 100 C. until a crosslinkedgel is formed. The gel is subsequently comminuted in an extruder or acutter-granulator and the precipitate is separate by filtration orcentrifugation. The resultant reaction product, which is a solid,infusible and insoluble urea-formaldehyde polymeric condensationproduct, is neutralized and dried by any conventional technique such asair drying and is then deagglomerated by means of an impact mill, an airjet mill or a ball mill.

The specific group of silicas useful in preparing the combinationflatting additive of the present invention include non-porous,pyrogenically prepared silicas having a surface area ranging from about30 to about 100 m. /g., and more preferably, a surface area ranging fromabout 40 to about 60 m. /g. In particular, the silicas contemplated foruse herein are prepared pyrogenically by the high temperature hydrolysisand/or oxidation of a volatilized silicon-containing compound such assilicon tetrachloride and are generally classified as fumed silicas. Thefumed silicas comprise particles of spherical shape and are ofexceptional purity in that the silica content is 99.8 percent.

As mentioned earlier, the components of the combination comprise anamount of from about to about 80 percent by weight urea-formaldehydepolymer based on the weight of the combination and an amount of fromabout 80 to about 20 percent by weight of fumed silica. The preferredembodiments of this invention, as recited hereinbefore, involvecombinations comprising amounts of from about 40 to about 60 percent 'byweight of ureaformaldehyde polymer and amounts of from about 60 to about40 percent by weight of fumed silica based on the weight of thecombination. The manner in which the ureaformaldehyde polymer and fumedsilica components are combined to form the novel flattening agentcompositions of the present invention is not critical. For example, thecomponents may be readily combined by simple dry mixing methods known tothe art, such as tumble mixing. Alternately, the blending of thecomponents may also be accomplished in situ, i.e., in the system whichis to be flattened or delustered, regardless of whether theureaformaldehyde polymer and fumed silica are dispersed or stirred-inseparately or together into the film forming system. Moreover, the orderof addition of the urea-formaldehyde polymer and the fumed silica to thefilm-forming polymeric material is of no particular significance.

In general, the delustered compositions of this invention are readilyprepared by dispersing the novel flatting additive formulations in thecompositions to be delustered. The flatting additive may be dispersed bysimply stirring the additive into the film-forming composition using anyconventional means for stirring such as a Waring Blender. 'It is to benoted that conventional flatting agents normally require grinding bymeans of a pebble mill, two roller mill or the like, to effectuatedispersion thereof into the composition to be flatted whereby thereproducibility of gloss values is adversely affected. In the presentcase, however, the use of the novel flatting combination comprised oftwo specific non-porous materials of suitable sizes and complementaryproperties eliminates the necessity of any grinding action to achievethe desired flatting effect and obtain a high degree of reproducibilityof gloss values. With respect to the percent solids of the resultantdelustered compositions, it is generally found that the total amount ofsolids, i.e., film-forming polymeric material and flatting additive,comprise from about 20 to about 60 percent by weight of the totalcomposition. In a preferred embodiment, however, the total solidscomprise an amount of from about 20 to about 45 percent by weight basedon the weight of the total delustered composition. For many purposes, itmay be desirable to incorporate other conventional additives such asplasticizers, corrosion inhibitors, pigments and the like and, it willbe apparent that compositions containing such other additives are withinthe scope of this invention.

The invention will be more readily understood by reference to thefollowing examples which describe the advantageous and unexpectedresults achieved by the use of the additive formulations of the presentinvention in the prep aration of delustered compositions. There are, ofcourse, many other forms of this invention which will become obvious toone skilled in the art, once the invention has been fully disclosed, andit will accordingly be recognized that these examples are given for thepurpose of illustration only, and are not to be construed as limitingthe scope of this invention in any way.

In the following example there are described representative insoluble,infusible, particulate, non-porous ureaformaldehyde polymers useful inthe preparation of the flatting combinations of the present inventionand methods for the preparation thereof.

EXAMPLE A To a suitable reaction vessel having means for the additionand removal of heat, means for measuring the temperature of the reactionmass and means for agitating the reaction mass, there is charged asolution comprising 0.315 part by weight of a sodium salt of a highmolecular weight carboxymethylcellulose of the type 7HP sold byHercules, Inc., dissolved in 15.75 parts by weight of water. To thissolution 22.5 parts by weight of an aqueous 30% formaldehyde solutionare added and the resultant mixture is heated to a temperature of about70 C. and adjusted to a pH value of about 7 with a sodium hydroxidesolution. There is then added with agitation 9 parts by weight of urea.'Upon completion of the addition of the urea, the condensation reactionis allowed to proceed, with agitation, for a period of 3 hours while thetemperature of the reaction mixture is held at about 70 C. and the pH ismaintained at a value of about 7. The precondensate reaction productthus obtained is cooled to a temperature of about 50 C. and rapidlymixed with a crosslinking agent-containing solution comprising 0.485part of sulfamic acid dissolved in 15.75 parts of water which has beenheated to a temperature of about 50 C. Gel formation occurs following aperiod of 12 seconds at which time the temperature of the reactionmixture rises to about 65 C. The gel is maintained under adiabaticconditions for 3 hours at a temperature of 65 C. Thereafter, the gel iscomminuted to a granular size of about 1 to 2 millimeters in a cuttergranulator, slurried with an equal volume of water and neutralized to apH value of 7.5 with a sodium carbonate solution. The resultant solidmaterial is separated by filtration, washed with 60 parts of water,dried at 110 C. in a current of hot air, cooled to room temperature anddeagglomerated by passage thereof through a high speed pin milloperating at 20,000 r.p.m. There is obtained 11.7 parts by weight of afine, white, powdery, non-porous, insoluble and infusibleurea-formaldehyde polymer having a BET specific surface area of about 53square meters per gram, a molar ratio of urea to formaldehyde of 1:15, atrue specific gravity of about 1.4, and a pour density of about 60 gramsper liter.

EXAMPLE B To a suitable reaction vessel having means for the addtion andremoval of heat, means for measuring the tem-- perature of the reactionmass and means for agitating the reaction mass, there is charged asolution comprising 0.315 part by weight of a sodium salt of a highmolecular weight carboxymethylcellulose of the type 7HP sold byHercules, Inc., dissolved in 15.75 parts by weight of Water. To thissolution 22.5 parts by weight of an aqueous 30% formaldehyde solutionare added and the resultant mixture is heated to a temperature of about70 C. and adjusted to a pH value of about 7 with a sodium hydroxidesolution. There is then added with agitation 9 parts by weight of urea.Upon completion of the addition of the urea, the condensation reactionis allowed to proceed, with agitation, for a period of 2 hours while thetemperature of the reaction mixture is held at about 70 C. and the pH ismaintained at a value of about 7. The precondensate reaction productthus obtained is cooled to a temperature of about 50 C. and rapidlymixed with a crosslinking agent-containing solution comprising 0.441part of sulfuric acid dissolved in 15.75 par-ts of water which has beenheated to a temperature of about 50 C. Gel formation occurs following aperiod of 7 seconds at which time the temperature of the reactionmixture rises to about 65 C. The gel is maintained under adiabaticconditions for 2 hours at a temperature of 65 C. Thereafter, the gel iscomminuted to a granular size of about 1 to 2 millimeters in a cuttergranulator, slurried with an equal volume of water and neutralized to apH value of 7.5 with a sodium carbonate solution. The resultant solidmaterial is separated by filtration, dried for hours at 110 C. in astream of air, cooled to room temperature and deagglomerated by passagethereof through a pin mill operating at 20,000 r.p.m. There is obtained13.6 parts by weight of a fine, white, powdery, non-porous, insolubleand infusible urea-formaldehyde polymer having a BET specific surfacearea of about 31.8 square meters per gram, a molar ratio of urea toformaldehyde of 1:1.5.

EXAMPLE C To a suitable stainless steel reaction vessel, equipped withmeans for addition and removal of heat, means for agitation andtemperature recording means, there are charged .75 parts by weight ofwater and 22.5 parts by weight of an aqueous formaldehyde solution. Themixture is heated to a temperature of about 70 C. and the pH value isadjusted to 7 with a solution of sodium hydroxide. There is then addedwith agitation 9 parts by weight of urea. Upon completion of theaddition of the urea, the temperature of the reaction mixture is held atabout 70 C. and the pH value at 7 while the condensation reactionproceeds for a period of about 2 hours. The resultant precondensatereaction mixture is then cooled to a temperature of about 50 C. and israpidly mixed with a curing catalyst-containing solution comprising0.485 part of sulfamic acid dissolved in 15.75 parts of water whichsolution is maintained at 50 C. Formation of a gel commences after a 12second period, at which time the temperature of the reaction mixturerises to about 60 to 65 C. The gel thus obtained is maintained underadiabatic conditions at a temperature of about 65 C. for about 2 hours.The resultant gel is then comminuted to a granular size of from about 1to about 2 millimeters in a conventional cutting granulator apparatus,slurried with an equal amount of water and neutralized to a pH value of7.5 with a solution of sodium carbonate. The solid product is recoveredby filtration, dried at 110 C. in a stream of hot air for 5 hours andcooled to room temperature. The resultant product is then deagglomeratedby passing the product through a high speed, i.e., 20,000 r.p.m., pinmill. There is obtained 13.6 parts by weight of a fine, white, powdery,non-porous, insoluble and infusible ureaformaldehyde polymer having aBET specific surface area of about 28.1 square meters per gram, a molarratio of urea to formaldehyde of 1: 1.6.

The following testing procedures are used in evaluating the physicalproperties and efficiency of the blended flatting agents of the presentinvention. It is, however, not intended that this invention be limitedby or to such examples.

Fineness of grind.-The degree to which a pigment is dispersed in a paintvehicle is measured in accordance with ASTM Test Method D1210-54utilizing a fineness of grind gage equipped with a Hegman scale ranginfrom 0 to 8.

Specular gloss.The degree of flatting or the diffusion of reflectedlight from the surface of a fihn is measured pursuant to the methoddescribed in ASTM Test No. D-52367, utilizing a Lockwood and McLorieModel J-3 Glossmeter. In making the determinations of degree offlatting, a beam of incident light is directed at an angle of 60, 20and/or degrees to the surface of, in this instance, a white glass plateon which there is a drawdown coating of a dry film having a thickness of1 /2 mils. In the event that the film has a perfect gloss surface thenthe light reflectance from the surface is of the same intensity and inthe same angular direction as the incident light. This is termedspecular, whereas a film which completely difluses reflected light istermed non-specular. A comparison of the intensity of reflected lightwith the intensity of the incident light indicates the degree ofdiffusion of reflected light and the degree of flatting efficiency.

Apparent viscosity (Brookfield).Apparent viscosities are measured bymeans of a Brookfield viscometer oper-'- ated at spindle speeds of 12r.p.m. and 30 r.p.m., in some cases, and at speeds of 6 r.p.m. and 60r.p.m., in other instances. The particular instrument employed herein isa Borokfield Rotary viscometer Model LVT, produced by BrookfieldEngineering Labs, Inc., of Stoughton, Mass. The Shear Thinning Index(S.T.I.), which is a measure of the shear sensitivity of a sample, isdetermined by measuring apparent Brookfield viscosities of the sample attwo spindle speeds. The Shear Thinning Index is then obtained by merelydividing the value for viscosity measured at the lower spindle speed bythe viscosity obtained at the higher spindle speed.

EXAMPLES 1-6 {Water-soluble, thermosetting acrylic polymer lacquers asshown in Table I containing varying proportions of the combined flattingadditive of the present invention are prepared as follows. There arecharged into a suitable reaction vessel Bakelite Acrylic Resin 200 whichis the registered trademark for a 55 percent solids solution of awater-soluble ther-mosetting acrylic polymer produced and sold by UnionCarbide Corporation. To the watersoluble thermosetting acrylic polymersolution there is then added isopropyl alcohol as a solvent mediumtherefor, the non-porous, particulate, pigmentary urea-formaldehydepolymer of Example A, and Cab-O-Sil L-5, a non-porous, pyrogenic silicaproduced by Cabot Corporation having an average ultimate particle sizeof about 0.05 micron, a surface area of about 50 mF/gm. as determined bythe Brunauer-Emmett-Teller (BET) method described in an articleappearing in the Journal of the American Chemical Society, vol. 60, p.309 (1938), a density of 7 lbs./cu. ft, a loss of 0.5% on ignition at1000 C., a pH of 4, and a silica content of 99.8 percent. The mixture isthen stirred for minutes in a blender such as a Waring Blender at a rateof about 20,000 r.p.m. to efiectuate an adequate dispersion. Thereafter,the resulting flatted lacquer compositions are subjected to testing forfineness of grind, apparent viscosities and degree of flatting and theresults of such measurements are reported below in Table I.

TABLE I TABLE II Composition (in grams) of- Ex. 7 Ex. 8 Ex. 9

Bakelite acrylic resin 200 200 200 200 Isopropyl alcohol 167 167 167Cab-O-Sil L-5 33 17. 5 Non-porous, pigmentary ureaiormaldehyd 15. 5Percent solids 35. 75 35. 75 35. 75 Grams flatting e nt per 100 resinsolids 30 30 Percent urea-formaldehyde by wt. of

combined flatting agent; 0 25 47 Broolcfield a parent viscosit 6 r.p.mcps.) 32, 600 18, 400 5, 640 60 r.p.m. (cps.). 3, 860 2,310 1,024 Shearthinning index. 8,4 8 5. 5 Specular gloss readings 60 gloss 31. 7 23. 316. 4 85 gloss 76. 1 29. 5 10. 6 20 gloss 31 5. 1 2. 5

Specular gloss readings are average of two highly reproducible glossreadings.

A revlew of the above results given m Table H shows that the degree offlatting efiect can be readily regulated by varying the ratio of the twocomponents of the flatting Composition (in grams) oi- Ex. 1 Ex. 2 Ex. 3Ex. 4 Ex. 5

60 85 gloss 20 gloss Mixtures stirred at a rate of about 20,000 r.p.m.

A study of the results for fineness of grind indicates that gooddispersion for low luster lacquers is obtained. Moreover, from the abovetabulated data, it becomes apparent that the gloss levels may beadjusted to the desired extent by increasing or decreasing the amount offlatting agent present in the lacquer composition. Furthermore, it is tobe noted that the gloss readings shown in Table I are, in fact, thedesirable levels at which flatted compositions of various levels can beobtained. It is thus obvious that the present combined flatting agentimparts many desirable properties to the composition to be delusteredwhile, in addition, replacing conventional pebble milling or grindingwith a stirring-in method for dispersing the flatting agent. As statedhereinbefore, the reported gloss readings are averages of two observedgloss readings which are characterized by a high degree ofreproducibility.

EXAMPLES 7-9 Lacquer compositions are prepared, pursuant to theprocedure of Example 1, by stirring, in any suitable means, such as aWaring Blender, at a rate of about 20,000 r.p.m. a mixture comprisingBakelite Water-Soluble Acrylic Resin 200, isopropyl alcohol, Cab-O-SilL-5 pyrogenic silica produced by Cabot Corporation, and the non-porous,pigmentary urea-formaldehyde polymer of Example A which is characterizedby having a BET specific surface area of about 53 m. /g., and a molarratio of urea to formaldehyde of 1:1.5. The results obtained on theselacquer compositions are given in the following Table II.

0a to co n to agent while keeping constant the total amount of flattingagent.

The novel and improved combinations of non-porous, pigmentaryurea-formaldehyde polymers and non-porous, pyrogenic silicas of thepresent invention are found to possess good settling and dispersioncharacteristics when utilized in delustering clear finishes. Moreover,from the foregoing results it is evident that the degree of flattingimparted to an organic polymeric film-forming composition can becarefully regulated either by varying the amount of flatting agentpresent in the composition as shown in Table I, or by varying the ratioof the two components of the flatting agent, as shown in Table II.

While this invention has been described with respect to certainembodiments, it is not so limited, and it should be understood thatvariations and modifications thereof may be made which are obvious tothose skilled in the art without departing from the spirit or scope ofthe invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A composition of matter comprising a film-forming organic polymericmaterial, an organic solvent for the film-forming organic polymericmaterial, and as a flatting agent for the composition a combinationconsisting of an amount of from about 20 to about percent by weight ofthe combination of a nonporous, infusible, insoluble, paticulate,pigmentary urea-formaldehyde polymer having a molar ratio of urea toformaldehyde ranging from about 1:1 to about 1:2 and a BET specificsurface area ranging from about to about 100 square meters per gram andan amount of from about 80 to about 20 percent by weight of thecombination of a non-porous, fumed silica having a surface area rangingfrom about 30 to about 100 square meters per gram, a spherical shape anda silica content of 99.8 percent, wherein the combination is present inan amount sufiicient to decrease or deluster the gloss of thecomposition.

2. A composition as defined in claim 1 wherein the combination ispresent in an amount of from about 5 to about 30 percent by weight basedon the weight of the film-forming organic polymeric material.

3. A composition as defined in claim 1 wherein the combination comprisesan amount of from about 40 to about 60 percent by weight of thecombination of the urea-formaldehyde polymer and an amount of from about60 to about 40 percent by weight of the combination of the fumed silica.

4. A composition as defined in claim 1 wherein the urea-formaldehydepolymer has a BET specific surface area ranging from about 50 to about80 square meters per gram.

5. A composition as defined in claim 1 wherein the fumed silica has asurface area ranging from about 40 to about 60 square meters per gram.

6. A composition as defined in claim 1 wherein the non-porous,insoluble, infusible, particulate urea-formaldehyde polymer has a molarratio of urea to formaldehyde of 1:15 and a BET specific surface area ofabout 53 square meters per gram and the non-porous, fumed silica has asurface area of about 50 square meters per gram, a spherical shape, anaverage ultimate particle size of 0.05 micron, and a silica content of99.8 percent.

7. A composition as defined in claim 1 wherein the solids content,including film-forming organic polymeric material and flatting agent,varies from about 20 to about 60 percent by weight based on the totalweight of the composition.

8. A composition as defined in claim 1 wherein the solids content,including film-forming organic polymeric material and flatting agent,varies from about 20 to about percent by weight based on the totalweight of the composition.

9. A composition as defined in claim 1 wherein the film-forming organicpolymeric material is a water-soluble, thermosetting acrylic polymer.

10. A composition as defined in claim 1 wherein the film-forming organicpolymeric material is a drying oil.

11. A composition as defined in claim 1 wherein the film-forming organicpolymeric material is an alkyd resin.

12. A composition as defined in claim 1 wherein the film-forming organicpolymeric material is a cellulose ester.

13. A composition as defined in claim 1 wherein the film-forming organicpolymeric material is a nitrocellulose.

14. A composition as defined in claim 1 wherein the film-forming organicpolymeric material is a polyurethane resin.

References Cited UNITED STATES PATENTS 2,541,975 2/1951 Bird 260392,858,284 10/1958 Acker et al. 26038 3,499,778 3/1970 Cain, Jr. et al.106288 3,656,981 4/1972 Beschke et al 106288 OTHER REFERENCES Chem.Absts., vol. 70, 1969, Formulation of Solvent Based Flat Coatings,3896ix, Feig.

WILLIAM H. SHORT, Primary Examiner E. WOODBERRY, Assistant Examiner US.Cl. X.R.

260-18, 21, 32.8 R, 33.4 R, 33.6 R, 39 P R SB, 851

